1. Field
The present invention relates to a method and system for automated control of transmission ratio change. More specifically the present invention relates to a method and system for automated control of transmission ratio change which balances the requirements for power with energy efficiency.
2. Description of the Related Art
In an increasingly busy world, a driver of a vehicle often needs to move from a first location to a second location in a rapid manner. To accomplish this goal, the driver may need to change lanes and/or pass another vehicle in front of his vehicle. However, a time frame to change lanes and/or pass another vehicle is often limited due to an abundance of other vehicles in the other lanes. Thus, to change lanes, the driver must often accelerate the vehicle rapidly. However, due to rising energy costs and a global concern for global warming, conventional vehicles are designed to be fuel efficient when a relatively constant speed or low acceleration is required. To conserve energy, the transmission utilizes a low transmission ratio when the vehicle is traveling in a relatively constant speed or low acceleration.
The low transmission ratio, while relatively energy efficient, produces an insufficient amount of power or torque to rapidly accelerate the vehicle. Thus, the transmission ratio must be increased to reach a target transmission ratio required to accomplish the desired rapid acceleration. However, conventional vehicles do not increase the transmission ratio until there is a user indication that the transmission ratio should be increased, such as when the user sufficiently depresses on the gas pedal.
When the user depresses on the gas pedal, there is a delay in increasing the transmission ratio due to the time required for hydraulic fluid to be filled in the appropriate components of the transmission and also the potential necessity to increase the transmission ratio not once, but multiple times to reach the target transmission ratio. Therefore, there is a delay in increasing the vehicle acceleration after the user depresses on the accelerator pedal. This delay can reduce the ability of the user to sufficiently accelerate the vehicle in the time frame required to change lanes and/or pass another vehicle. The delay can therefore cause the user to have to sharply apply the brakes of the vehicle since he is unable to change lanes, or worse, cause the vehicle to crash into another vehicle or object.
Thus, there is a need for a method and system for automated control of transmission ratio change which balances the requirements for power with energy efficiency.